Sharon D Clarke, 50, grew up in Tottenham, north London, the daughter of working-class Jamaican parents, and first trained as a social worker. She had a top 10 hit with Nomad’s (I Wanna Give you) Devotion in 1991, and from 2005-8 played Lola Griffin on Holby City. Highlights of her stage career include Ghost,The Amen Corner, for which she won an Olivier award, and Ma Rainey’s Black Bottom. She was described as “ever-magnificent” and “incomparable” in reviews of her last musical, The Life, at Southwark, and next month leads the Chichester festival theatre production of Tony Kushner and Jeanine Tesori’s 2003 civil rights musical Caroline, Or Change. Clarke is married to an executive producer of Hackney Empire, Susie McKenna.

Your character, Caroline, is a black single mother and a maid to a Jewish family in Louisiana in 1963. Where does the musical go from there?It’s about a woman trying to reconcile herself with the change that is happening around her. JFK’s been shot, her daughter is becoming part of the new black civil rights movement, while she is very much of the old school – she says “coloured” and “negro”. Her boss, Rose Gellman, also lets Caroline keep any change Rose’s son Noah leaves in his pocket: its pennies and nickels but could make a difference between her own kids having meat that week or not. How does accepting pennies that are a child’s leftovers affect her self-worth?

Is a through-composed work [little or no dialogue] like this more demanding?Not for me, really. In musicals you sing when, emotionally, there is nowhere else you can go. Because this is through-composed, you get that heightened emotion all the way through. I saw the [2007 UK] production at the National and loved the music, this melting pot of opera, gospel, blues and klezmer. And as a role it’s a real tour de force. It’s not cabaret singing: you have to act every minute of it.

Caroline also talks to her kitchen appliances…I see them as the souls of her ancestors. They represent people who keep her in check, support her, encourage her and sometimes belittle her – she and the dryer do not have a great relationship [laughs].

Does the show feel timely?Oh God yes, come on! Doing this show at this present time, with everything going on in the world, is a great reminder of why we need to keep looking back on history and not make the same mistakes.

Have roles got better for black and female actors since you started out?I’ve been lucky. I saw Amen Corner at the Tricycle, and Ma Rainey’s Black Bottom at the National, in 1989: I saw Caroline, Or Change 10 years ago, and these are roles I’ve now been able to do. The Life I loved for 20 years, and never thought it would come to Britain, but it did and I was lucky enough to do that. I don’t actually see a lot of TV: Line of Duty caught me, but there’s not a great deal of black folks in that. I enjoyed The Life and am enjoying this show because they have multiracial casts: as a Londoner, that’s what I know. I would like to see that reflected more on stage and on TV.

Sharon D Clarke and cast in The Life at Southwark Playhouse. Photograph: Tristram Kenton for the Observer

What was it like playing the bad fairy Carabosse in the Hackney Empire’s last panto, Mother Goose, written and directed by your wife Susie?My mum passed away last year so I wanted to be working over Christmas, rather than sitting around mourning, but I didn’t want to just do anything. Susie said, do you want to come to Hackney? And I said, yeah, I want to be with family, with people who know me inside out, so if I am crying in a corner they will completely understand. And, I said, I want to be a baddie: I’ve never been one. Because she is my wife, Susie can write for me better than anybody. So Carabosse was a joy and quite cathartic.

What’s your vocal range?I call myself an alto. I visit high notes but I don’t live there. Even my speaking voice is low: when I answer the phone I always get ‘how can I help you, sir?’.